Compensating plate means for bone fractures



United States Patent zm'nn T em N 171mm! OTHER REFERENCES FractureEquipment by Zimmer, Zimmer Catalog, Zimmer Mfg. Co., Warsaw Indiana,Feb. 1, 1947, Vitallium Screws, page 37. Copy available in Group335.128/92B Combination Smoplates, Zimmer Mfg. Col Catalog, Warsaw,Indiana, page 124, picture No. 339, 1950, received in Group 335 Mar. 23,1954.

Primary ExaminerRichard A. Gaudet Assistant Examiner-Ronald L. FrinksAttorney-Jacobs & Jacobs ABSTRACT: Fractured bones subject tocompressive and tensile forces are provided with compensating platemeans attached to the fractured bone and extending across the site ofthe fracture to hasten fusion of the fractured joint. The compensatingmeans may take the form of a plate one end of which is fixedly securedto the bone above or on one side of the fracture site and the other endof which permits, due to a special type of connection, relative limitedbone movement below or on the other side of the fracture site to takecare of compressive and tensile forces acting on the bone. In a modifiedform of the invention, two relatively slidable plate sections, one ofwhich has an enlarged hollow casing, are provided which can telescopeunder the influence of the compressive forces.

COMPENSATING PLATE MEANS FOR BONE FRACTURES The present inventionrelates to compensating plate means especially adapted to be applied tofractured bones and which is so constructed and designed thatcompressive or tensile forces acting on the fractured bone areautomatically compensated for. Bone misalignment or separation isprevented and fusion of any of the major joints of the body is hastened.The invention is useful for any fractured bone where application of thecompensating plate means is surgically or mechanically possible or formedical demonstration or educational purposes.

In the accompanying drawing:

FIG. 1 is an elevational perspective view of a part of a fractured bonewith the preferred form of the invention applied thereto;

FIG. 2 is a fragmentary sectional view taken along line 2-2 of FIG. I;

FIG. 3 is a face view of the toothed or serrated disc element of FIG. 2;

FIG. 4 is a view similar to FIG. 1 wherein a modified form of theinvention is used;

FIG. 5 is in part a sectional view taken on line 5-5 of FIG. 4; and

FIG. 6 is a sectional view taken on line 6-6 of FIG. 5.

Referring to the preferred and best mode of carrying out the inventionas shown in FIGS. 13, the numeral 10 designates portions or fragments ofa bone which has been fractured, the site of the fracture beingindicated at 11. The arrows 12 show the direction of compressive axialforces acting on the fractured bone by the weight of or during movementsof the patient. A plate- 13, preferably of elongated rectangular shapeand of a suitable thickness and material, is permanently secured at oneend to that portion of the bone 10 which is above or on one side of thefracture site 11 and this can be carried out by any suitable fasteninginstrumentalities such as the screws 14, which are preferablyflat-headed and which may optionally be countersunk.

It will be seen that plate 13 also extends below or to the other side ofthe fracture site 11 of bone 10 and is provided with an elongated oroval slot or aperture 15 surrounded, on the surface of the plate, byratchet teeth or serrations l6 and through such slot or aperture 15 aspring washer screw I7 (Belleville spring washer) is adapted to bepassed and screwed into the bone while still, however, enabling thelower portion of bone 10 below the fracture site a certain limited andcontrolled amount of vertical movement depending upon the length of theopening 15 and the compressive or tensile forces acting on the fracturedbone at any given instant. Spring washer screw 17 has shank 17'extending into bone fragment 10, a disc 17" having teeth or serrations17"" and a spring washer 17" all arranged as shown in FIG. 2. Only onesuch screw with ratchet and slot is required. The other screws 17 affordadded stability without interfering with the action of the screw withratchet and slot.

The plate 13 can be composed of stainless steel or other metal or alloy,synthetic plastic or any physiologically acceptable, sterilizablematerial having requisite strength and rigidity and its exact shape,length, width and thickness depend upon the particular bone or joint andits size and the location of the fracture site. It will thus be seenthat in a safe, simple and effective manner compressive forces on bone10 push the bone fragments together and keeps them aligned whereas ifthe fracture site collapses the mating ratchet teeth allow the fragmentsto move closer but restrain extension due to tensile force.

In the modified form of the invention illustrated in FIGS. 4- -6, theportion of the bone 10 above the fracture site 11 is provided with aplate 13a similar to the upper portion of plate 13 ,and similarlyprovided with securing screws 14a, but the plate 130 is relatively shortin length as will be observed and at its lower end flares out into ahollow casing 18 which is smooth on its external surface, but which isprovided with inclined notches (cam surfaces) 19 on its inner surface.The

remainder of the compensating plate means of this form of the inventionis made up of a separate lower plate 20 permanently secured as by screws14a to a portion of bone I0 below the fracture site 11 and this lowerplate 20, as will be best seen from FIG. 5, extends upwardly into thecavity 2] within the hollow casing 18 and can move in a guidedcontrolled manner vertically upwardly and downwardly with relation tocasing 18. In addition, ball bearings 22 are located in the spacesformed between the cam surfaces 19 and the adjacent surface or edge oflower plate 20 and due to the construction of the cam surfaces and theshoulders 23 thereof together with the inclination of the bottom of thenotches, acts to limit the vertical up and down movement of lower plate20 with respect to casing 18 responsive to forces acting on thefractured bone. The dimensions and construction are such as to take careof all normal compressive or tensile forces acting on the fracturedbone. This modified form of the invention while somewhat less simple inconstruction than the preferred form of the invention, is particularlysuitable for certain types of bone fractures or fracture site locationswithin the judgement of the surgeon or other technician, and furtherdepending on the particular bone which is fractured and the amount ofrelative movement to be expected from the portions of the bone 'on eachside of the fracture.

It is further understood that parts or elements of the invention such asl5, l6 and 17 in particular are exaggerated as to size for clarity ofillustration and that the drawing is not to be interpreted as settingforth scale or relative sizes. The distance R in FIG. 5 shows the rangeof compensation of that form of the invention. When the parts are undercompression, the plate sections telescope and the overall length of theplate becomes shorter; when under tension the ball bearings and inclinednotch (cam) surfaces lock the two sections to prevent extension.

I claim:

l. Compensating plate means for bone fractures comprising a flat, solid,one-piece serrated plate made from physiologically acceptable materialwith apertures spaced therealong adapted to be placed in contact with afractured bone across the fracture site, first means passing throughsome of the apertures for securing one end portion of the plate to thefractured bone on one side of the fracture site and second means passingthrough another aperture and adapted to be responsive to compressive andtensile forces acting on the bone for securing the other end portion ofthe serrated plate to the fractured bone on the other side of thefracture side, said second means having a head with an attached shankextending through said another aperture, the length of said anotheraperture being greater than the diameter of said shank, a serratedwasher mounted around said shank having its serrations in engagementwith the serrations on said plate, a spring means interposed between theundersurface of said head and in engagement with the top surface of saidserrated washer, whereby relative movement between said plate and saidsecond means is possible in response to compressive and tensile forcesacting on said fractured bone.

2. Compensating plate means for bone fractures according to claim 1wherein the firs't means includes flat-headed screws extending throughthe plate.

3. Compensating plate means for bone fractures according to claim 2wherein said head and shank defines a spring washer screw and saidanother aperture is an elongated slot extending through the plate.

